Now look who’s one win away from the World Series.

The Boston Red Sox, playing like the defending champs they are, came out swinging and beat Tampa Bay 4-2 Saturday night to force a Game 7 in an AL championship series the Rays all but wrapped up two days ago.

Jason Varitek snapped an 0-for-14 slide with his tiebreaking, sixth-inning solo homer off James Shields. Kevin Youkilis also homered off the Rays starter.

Red Sox ace Josh Beckett, who struggled in his first two starts of the playoffs, allowed two runs and four hits in five innings, and Hideki Okajima, Justin Masterson and Jonathan Papelbon combined for hitless relief.

‘‘The important thing is we found a way to win this game,’’ Varitek said. ‘‘It was a big win for us.’’

The young Rays were seven outs from their first pennant when their trusty bullpen allowed a 7-0 lead slip away over the last three innings of Game 5 at Fenway Park. Boston’s 8-7 comeback victory was the biggest postseason deficit overcome since 1929.

B.J. Upton tied an AL record with his seventh home run of the postseason. After Boston went ahead 2-1, Tampa Bay tied it on Jason Bartlett’s fifth-inning homer. But the Rays didn’t get another hit, and the Red Sox improved to 9-0 in ALCS elimination games under manager Terry Francona.

Now Jon Lester starts Game 7 for the Red Sox on Sunday night against Matt Garza in a rematch of Game 3, won by the Rays 9-1 at Fenway Park. The winning team hosts the World Series opener Wednesday night against the well-rested Philadelphia Phillies, who won the NL pennant over the Los Angeles Dodgers in five games.

‘‘It’s great to get to Game 7, to battle like this,’’ Youkilis said. ‘‘We went out there and played like it was our last game. It was awesome.’’

Boston bounced back from a 3-1 ALCS deficit in 1986 against the Angels, then in 2004 became the first major league team to win a postseason series when trailing 3-0, beating the Yankees for the pennant before sweeping St. Louis in the World Series.

Last year, the Red Sox trailed Cleveland 3-1 before winning three in a row, then sweeping Colorado for their second Series title in four seasons.

It was a strange night in different ways. The first 20 minutes of the game weren’t shown on television because TBS had an equipment failure.

And plate umpire Derryl Cousins left with a bruised collarbone after three innings, causing a 15-minute delay. Cousins was struck by a foul ball hit by Varitek in the second, but remained in the game until the delay. He was replaced by crew chief Tim McClelland, who had been working first base.